Safety catch



l. HANSEN SAFETY CATCH Filed Feb. 12, 1929 2 Sheets-Sheet 1 lbtom Aprila, 1930. I. HANSEN 1,752,987

SAFETY CATCH Filed Feb. 12, 1929 -2 Sheets-Sheet 2 Patented Apr. l, 1930 PATENT ISAK HANSEN, OF ROCHELLE, NEW YORKY SAFETY CATCH Application led February- 12, 1929. Serial No.` 339,321.

This invention relates to lifts, and more particularly to an automatic safety catch for preventing a lift from falling upon failure of the supporting mechanism.

The invention applies particularly to lifts which are supported by a single cable secured to the top portion thereof, as foryexample, dumbwaiters, and provides means for locking the lift if the cable becomes slack either due to breakage or due to interruption of the downward movement`of the lift, such as by increased friction of the guiding mechanism which might cause the lift to stick temporarily. If the descent of the lift is interrupted while the cable is being fed downwardly the cable will become loose and when the lift is subsequently released will allow thesame to drop until the cable again becomes tight. The force of this drop has at times been suflicient to damage the mechanism, or in the case of wooden dumbwaiters, to sever .the connections betwen the cable and the top thereof.`

In accordance with the present invention whenever the cable becomes loose the safety catch is automatically applied and prevents further descent until the supporting cable is again tightened. This prevents the lift from dropping and in fact prevents all further movement until it is again raised by reversing the movement of the supporting table. f

The invention comprises a gripping member which is normally carried on the lift in an inoperative position, but which is released and is brought into engagement with the guideway of the lift whenever the supporting cable becomes loose. The grip is normally held out of engagement with the guideways by a resilient member and is accordingly prevented from causing wear of the guideways except when it is brought into operation as a safety catch.

The invention also consists in certain new and original features of vconstruction and combinations of parts hereinafterset forth and claimed.

Although the novel features which are believed to be characteristics of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which Fig. l is a plan view of a lift showing a pair of safety catches applied thereto;

Fig. 2 is an enlarged detailview of the safety catch and the supporting cable;

Fig. 3 is a section taken on the line 3 3 of Fig. 2 showing the catch in disengaged position;

Figs. l and 5 are detail views of modifications of the gripping member;

Fig. 6 is an enlarged detail View of the control lever and supporttherefor; and

Fig. 7 is a detail of the clamp.

Lilre reference characters denote like parts in the several figures of the drawings.

In the following description and in the claims parts will be identified by specific names Afor convenience, but they are intended Yto be as generic in their application to'similar parts as the art will permit. V

vReferring to the drawings more in detail, the vinvention is shown as applied to a lift 10 which may comprise a dumbwaiteror other analogous device. The lift is provided with fingers 11 which engage with the guideways 12. A supporting cable'ld is lirmly secured to the top of the lift in any desiredmanner and serves to control the vertical position thereof. v

The safety catch as shownmore in detail in Fig. 2 comprises ahousing l5 which may be cast or formed in any other desired manner and is provided with a flange 16 which may be secured to the side 17 of the lift by any suitable means as by bolts 18. The housing is also provided with a pair of outwardly Vextending ears 20 through which suitable bolts 2l maybe passed for attaching the same to the top Aportion of the lift 10.

Housing 15 is drilled to receive a rock shaft such as a bolt 24 which is provided with a head 25 and a shoulder 26 for the purpose to be described. A second shoulder 27 is formed on the opposite end of said bolt, and threads 28 are' provided for receiving a nut 29 and a lock washer 30, by means of which the bolt is secured in position in said housmg.

The grip member 81 is provided with a recess which is inserted over shoulder 26 whereby said member is mounted for rotational movement with bolt 24. Lever 32. is also provided with a recess which is inserted over shoulder 27 of said bolt. The grip member and lever are preferably formed slightly thinner than theircooperating lshoulder-s .in order to prevent the same from bindingl when the bolt is tightly secured in housing 15.

Lever 32 is provided with` a hole in which one end of a spring 34 is secured. The `other end-of said spring is permanently secured-to the top of the lift as by pin The end of 1ever-32 is provided :with a hole 86 in which a flexible cable, such as wire 87, is

secured. Said wire is passed through eyes 40,41 (Fig. 1) which are secured in the top of lift 10, and is thence passed upwardly (Fig. 2) and secured t0 cable 14 by any suitable means such as clamp 42.

A type .of clamp which may be employed `is shown indetail yin 7 as comprising a bolt 6.0, Which may be insel-ted throughcable 14 in any convenient manner, such as by spreading the libersof the cable with a suitable tool and then threading the bolt between the separated fibers.

Clamps 61 and 62 are carried upon bolt y6() and are suitably curved to conform in gen- Veral tothe shape of cable 1,4. Clamp 63 is carried on bolt adjacent clamp 61 and is curved in conformity with the outer surface of clamp 61. .Grooves 6.4 and are formed in clamps63 and 61 respectively for receiving Wife i i -A The entire assembly is secured by nut 66 and look washer `67. It is obviousth-at pressure applied to said nut will-.cause clamp members 6.3 61 and 62 to firmly eng-agecable 14 and wire''?.

.Grip member y3l is preferably formed with a plurality of seizing elements such as short .point 45 and a, long point 46. The short point is adapted to engage the side of guide 12 when the member is rotated in response to the tensionof spring 34. If the weight of ,the lift is such that point, 45 `is sufliciently strong to secure the same, point` 46 will voperate merelyas an abutmentl but will not en- ,terztheguidemember. If, however, themechtends. to kdrop after point 45 becomes engaged, further rotation Aof the grip will ,take plaeetheleby bringing peint 46into ,engagement `With the guidey 12y for effectively checking the .descent of the lift. The amount of rotation-0f grip 31 is limiited suitable Shoulders 47 .(Fig. 6)z which are formed on heusimg 125 and; engage with lever .'32 when saicl lever-.ism its ,extreme position.

In `the modification shown in Fig.V 4, grip 49: is provided with aplurailityof points 50 which are positioned at different distances from the center of rotation of said grip. With this construction the upper point 50 will first be brought into contact with the guide member and the remainder of the points will be successively brought into contact therewith as .the grip is further rotated due to slippage of the lift. Itis-to be noted that the gripping force is accordingly increased asl required by an amount depending upon the tendencyof the lift to slide.

A second modification of the grip is shown in Fig. 5 which comprises a grip 52 formed with la single point 53 .which is adapted to be brought into engagement with guideway 12 in themanner above pointed out.

In order to prevent Athe slides, frombeing distorted Vdue to .the/action of the gripping members on one side thereof it may b e desired to prov-idea pair of such members as shown in F ig. V1 whichloperate in opposite directions whereby the lateral stress on the supporting mechanism is equaliaed The above described catch member is soplositioned `von thelift Jthat spring 3.4 will ncrmally .tend to hold the grip in engagement with `the guideway. The spring should be adjusted to lprovide the necessary force` for bringing this grip into engagement and for causing the Ypoints thereof ktoenter the -mate- ,-z-ial of the -guidewazy .as 4above mentioned. ,Flexible cable or Wire 37 which is secured to lever 32-is passed undereyes 40 and 41 and is lthen extended upwardly and secured to. cable `cable.14 becomes: loose,the tension ofwire 37 decreases, thereby permitting spring '34 toy bring the grip intoi operating position. f

It is toabevnoted that. side strain on. .cable 14 is. eliminated-.by positioning .eye .41 comparatively close-to. the point of attachment of cable 14 whereby-'the wireV and cab-le are caused to extend in the same general direction. 'The device above described isV particularly applicableto Wooden lifts', such as dumbwait-ers which are commonly securedI between wooden guid'eways. It is obvious, however, that `the `dev-ice maybe applied to other types of lifts'provided the parts are made accordingly stronger; Furthermore the grip may Contact with any stationary mem-ber; It is -shownas contacting with the guidevvays for lpurposes of' illustration only'- While certain novel features of the invention have/been shown and described andi are pointed out in the annexed; claims, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated andf its opera-tion maybe made by those skilled the art without departing from` the spirit ofthe invention.

What is claimed is:

1. In combination with a lift having a supporting cable, fruideways in Which said lift is adaptedto sl`de,asafety catch member comprising a grip member, resilient means for holding said grip member in engagement with said guidevvays, a lever associated with said grip member and a flexible member interconnecting said lever and said supporting cable, said member being threaded through members secured in the top of said lift, one of said members being located near the point of attachment of said supporting cable.

2. A safety catch for a lift comprising a housing, a bolt extending therethrough, said bolt having a head and a shoulder adjacent said head, a grip member carried on said shoulder, a second shoulder and a lever carried thereon, means associated With said lever for holding said grip member in operative position and additional means associated With said lever for moving said grip member to an inoperative position.

3. A clamping device for securing a iieX- ible member to a stranded cable comprising a bolt adapted to be passed through said cable, curved clamps carried by said bolt and adapted to engage said cable, a third clamp adjacent one of said curved clamps and having means for engaging said flexible member,

and means Jfor clamping said elements to-v gether for securely gripping said cable and flexible elements.

In testimony whereof I have hereunto set my hand.

ISAK HANSEN. 

